Temperature responsive imitating apparatus for a photographic camera

ABSTRACT

An exposure actuation system, preferably including an electric start switch for a photographic camera including a movable actuator button which is operative to initiate a photographic exposure only at predetermined temperatures. Depression of the movable actuator button is operative to move one electrical spring contact into electrical engagement with another spring contact for closing appropriate camera shutter circuitry. In a preferred embodiment, a liquid-filled elastic member is interposed in the path of movement of the subject actuator button. Should the photographic camera be subjected to temperatures below the freezing point of the liquid, the liquid freezes and prevents depression of the actuator button.

United states Patent [191 Land et al.

1111 3,824,611 1 51 July 16, 1974 [54] TEMPERATURE RESPONSIYE IMITATINGAPPARATUS FOR A PHOTOGRAPHIC CAMERA I [75] Inventors: Edwin H. Land,Cambridge; David V. Cronin, Peabody, both of Mass.

[73] 'Assignee: Polaroid Corporation, Cambridge,

Mass. [22] Filed: Dec. 26, 1972 [21] App]. No.: 318,228

[52] U.S. Cl..... -354/202, 354/266, 200/157 [51] Int. Cl. G03b 17/00[58] Field of Search... '95/11 R, 54, 1 R; 200/33 R, 61.04, 157

[56] References Cited UNITED STATES PATENTS 530,486 12/1894 Jensen 95/54Primary Examiner-Robert P. Greiner Attorney, Agent, or Firm-William A.Danchuk 5 7] ABSTRACT An exposure actuation system, preferably includingan electric start switch for a photographic camera including a movableactuator button which is operative to initiate a photographic exposureonly at predetermined temperatures. Depression of the movable actuatorbutton is operative to move one electrical spring contact intoelectrical engagement with another spring contact for closingappropriate camera shutter circuitry. In a preferred embodiment, aliquid-filled elastic member is interposed in the path of movement ofthe subject actuator button. Should the photographic camera be subjectedto temperatures below the freezing point of the liquid, the liquidfreezes and prevents depression of the actuator button.

12 Claims, 4 Drawing Figures PATENTEB JUL 1 6 i974 Fles- TEMPERATURERESPONSIVE IMITATING APPARATUS FOR A PHOTOGRAPHIC CAMERA BACKGROUND OFTHE INVENTION that is important. In cold weather, the camera user can.

step out of a warm house or car to snap a picture, immediately returningto the warm place for the development of his picture. However, if thetemperature of the camera and film during development is below apredetermined temperature, an inadequately developed picture may result.Moreover, if the temperature conditions are severe enough, nodevelopment may be possible. Therefore, users are usually instructed notto use the film under temperature conditions in which the film unitwould not provide acceptable results.

In addition to the temperature influence on photographic films, theremay be a similar influence on the mechanical components of both stilland motion picture cameras. With regard to still cameras, thetemperature effect is related to thefilm transport and exposure systems.The oil used to lubricate various elements within the transport systembecomes more viscous when subjected to cold. As such, damage to thesystem becomes likely when the camera is subjected to undesired lowtemperatures and actuation of the sameis attempted. With regard tomotion picture cameras, temperature effects are particularly related tothe responsiveness of the power source incorporated within thesecameras. In particular, the effective voltage produced by a battery isdirectly proportional to the temperature at which the battery isoperated. Accordingly, as the camera and battery are subjected to severecold, the latter produces voltages at decreased levels. This decrease inbattery voltage may render the camera inoperative.

SUMMARY OF THE INVENTION The present invention is addressed to atemperature dependent shutter actuation system, particularly an electricstart switch, for a photographic camera, the operability thereof being afunction of the ambient temperature. The start switch includes a movableactuator button which, when depressed, is operative to move.

one spring contact into electrical engagement with another for closingappropriate shutter circuitry. In one preferred embodiment, aliquid-filled elasticmember is interposed in the path of the actuatorbutton as it is depressed. Under normal temperature conditions, theliquid-filled member complies elastically with the actuation force onthe actuator button and a picture-taking cycle proceeds normally. Shouldthe temperature conditions be at or below freezing point of the filmunit and the camera and film are both very cold, then the liquidfilledelastic member freezes thereby preventing normal depression of theactuator button.

Although various liquids may be employed, it is obviously desirable touse a liquid whose freezing point is somewhat higher than that of theprocessing composition. As a result, the camera is inactuated at thesame temperature at which the processing composition in the film unitbecomes temporarily frozen. Additionally, a

liquid may be employedwhich exhibits an increasing viscosity withdecreased temperature. As such, there would be an increased resistancewithin the liquid itself which would be capable of preventing actuation,or at least making actuation so-difficult that the camera user would beprevented from actuating an exposure at lower'temperatures. The broadinventive concept of preventing actuation of a camera when the ambienttemperature is outside a predetermined temperature range is not ourjoint invention and is not the subject of the present application, butwas derived prior to the filing date of the instant application fromEdwin H. Land and is the subject matter of the invention disclosed andclaimed in application Ser. No. 338,322

' filed by Edwin H. Land on Mar. 5, 1973, said application Ser. No.338,322 being assigned to the assignee of the instant application.

OBJECTS OF THE INVENTION It is a general object and feature of thepresent invention to provide a temperature responsive start switch for aphotographic camera for rendering the camera temporarily inoperablebelow a certain predetermined temperature.

. provide a temperature responsive start switch for a It is anotherobject and feature of this invention to photographic cameracharacterized in having a flexible liquid-filled member, the freezingpoint of which is not less than the temperature at which film within thecamv era would not give useful results.

Further objects and advantages of the invention will in part be obviousand will in part become apparent as the following description proceeds.The features of novelty which characterize the invention will be pointedout with particularity in the claims annexed to and forming a part ofthis specification.

I BRIEF DESCRIPTION OF THE DRAWINGS 4 DETAILED DESCRIPTION OF THEDRAWINGS Referring to FIG. 1, there is shown a temperature responsivestart switch 10 for a photographic camera according to the presentinvention. An actuator button 12 for switch 10 is movably mounted withina housing 14 formed as part of a camera (not shown). Button 12 is formedwith a relatively large outer portion 16 and a relatively small innerportion 18. A connecting portion 20 of button 12 connects portions 16and 18 and extends through a bore 22 formed within housing 14. Innerportion 18 is configured having adiameter larger than that of bore 22thereby preventing the extraction of button 12 from housing 14.

Positioned behind housing 14 are a pair of contacts 24 and 26. Contacts24 and 26 are operative to connect appropriate exposure controlcircuitry (not shown) within the camera with an electrical power source(not shown) to initiate a photographic exposure. As such, contacts 24and 26 act as a switch. Contact 24 is flexible in nature and is capableof being moved by button 12 into contact with contact 26, the lattercontact being stationary. This closed position is best shown in FlG.'2;

Positioned between outer portion 16 of button 12 and housing 14 is atoroid Shaped elastic member 28. Member 28 is filled with a liquidwhich-has a predetermined freezing point. Due to the possibility ofinterchanging member 28 with various different liquids,

member 28 may have any one of several freezing points. At normaltemperatures, member 28 retains its elasticity and easily complies withthe actuation force on actuator button 12. The form towhich member 28 istransformed during actuation is best shown in FIG. 2. I

With the configuration shown, actuator button 12 is automaticallyreturned to its starting position (see FIG. 1) by forces derived fromflexible contact 24 and from liquid filled member 28 returning to theirunstressed positions. The operation of switch 10 will function asdescribed under temperatures above that of the predetermined freezingpoint of the liquid employedwithin member 28. r When the temperature towhich switch l-is subjected falls below the predetermined freezing pointof the liquid, however, switch becomes inoperative. The liquid freezes,solidifying member 28, thereby preventing the latters elastic compliancewith an actuating force on button 12.,As such, actuator button 12 isretained in its outwardmost position and switch 10 remains open. Nocamera actuation may now take place. When the temperature rises, thefrozen liquid melts and normal camera actuation is possible. i

A second embodiment of the present invention is shown in FIGS. 3 and 4.Looking to FIG. 3, there is disclosed a switch shown generally at 30.Switch 30 is configured, having a movable actuator button 32, a pair ofelectrical contacts 34 and 36, and a liquid-filled toroidalshaped'member 38. Button 32 is similar to the actuator button 12 in thefirst embodiment shown and may be mounted similarly although nostructure for such a mounting is shown. Located directly behind button32 is contact 34. Depression of button 32 moves contact,

34 into electrical connection with contact 36 the latter being heldstationary. The electrical connection between contacts 34 and 36 closesappropriate camera circuitry representively denoted by box 40. As may bereadily evidenced from FIG. 3, liquid-filled member 38 does notinterfere with the electrical connection described above. However, whenthe temperature falls below a predetermined point the liquid containedwithin member 38 freezes and expands. .Due to the stretchable nature ofmember 38, the expanded liquid is contained within member 38; As thefreezing liquid expands, member 38 is expanded outwardly from a wallstructure 42. As this expansion proceeds, contact 36 falls behind theforwardmost portion of member 38.

This position can be best seen by referring to FIG. 4. When the liquidis completely frozen and expanded, member 38 prevents electricalconnection between contacts 34-and 36. Accordingly, camera actuation istemporarily prevented and possible poor photographs or damage tospecific camera elements is avoided.

The selection of specific liquids for use within members 28 and 38depends upon the temperature at which 'deactuation of the camera startswitch is desired. For many circumstances, water would be suitable.However, should deactuation be desired to be only at temperatures below0 C, solutions having various degrees of salinity may be incorporatedwithin members 28 and 38. If saline solutions are undesirable, e.g.,because of possible corrosion, other aqueous or organic solutions may beselected by routine experimentation as having the desired'freezingpoint. 7

As may be evidenced from the foregoing, the temperature dependent switchof the invention provides the capability of preventing cameraactuationunder specific temperature conditions. The switch employs aliquid-filled elasticmember which, when frozen, prevents the movement ofone electrical contact into electrical connection with another contact.While the two embodiments shown are based upon an electrical system, itshould be obvious to those skilled in the art that the basic-principlesof the switch disclosed may be applied to a mechanical system.Accordingly, the switch would prevent mechanical actuation of acamerawhen temperatures'fall below a predetermined level. In both theelectrical and mechanical systems, however, possible damage to thecamera components wouldbe alleviated.

Since certain changes may be made in the above apparatus withoutdeparting from the scope of the invention herein involved, it isintended that all matter contained in theabovedes'criptionor shown inthe accompanying drawings shall be interpreted as illustrative and notin a limiting sense. What is claimed is: 1. A temperature dependentshutter release for a photographic camera, said temperature dependentshutter release comprising:

ahousing; actuator means extending through said housing, said actuatormeans being movable between a first position in which said shutterrelease is open and a second position in which said shutter release isclosed; and

liquid-filled means operative to prevent said actuator means from movingfrom said first position to said second position when the temperature ofsaid liquid-filled means is below a predetermined position,

' said liquid-filled means being formed as an elastic toroidal shapedmember having a quantity of liquid contained therein, said elastictoroidal shaped member being positioned between said housing and saidactuator means.

2. The temperature dependent shutter release of claim 1 in which saidliquid contained within said elastic toroidal shaped member is selectedhaving a predetermined freezing point, said elastic toroidal shapedmember being operative to prevent said movement of said actuator meansfrom said first position to said second position whensaid photographiccamera is subjected. to temperatures below said predetermined freezingpoint of said liquid.

3. The temperature dependent shutter release of claim 2 in which saidelastic toroidal shaped member is operative to comply with said movementof said actuator means from said first position to said second positionwhen said photographic camera is subjected to 5. The temperature.dependent shutter release of claim 4 in which said liquid containedwithin said elastic toroidal shaped member is a saline solution.

6. A temperature dependent shutter release for a photographic camera,said temperature dependent shutter release comprising:

a housing;

actuator means movable between a first position in which said shutterrelease is in a pre-exposure status and a second position in which saidshutter release initiates a photographic exposure; and liquid-filledmeans including a liquid contained I therein having a predeterminedfreezing point, said liquid-filled means being operative to prevent themovement of said actuator means from said first position to said secondposition when said photographic camera is subjected to temperaturesbelow said predetermined freezing point of said liquid.

7. The temperature dependent shutter release of claim 6 in which saidliquid-filled means is operative to elastically comply with saidmovement of said actuator means from said first position to said secondposition when said camera is subjected to temperatures above saidpredetermined freezing point of said liquid.

8. The temperature dependent shutter release of claim 7 in which-saidliquid contained within said liquid-filled means is an aqueous solution.

9. The temperature dependent shutter release of claim 8 in which saidilquid contained within said liquid-filled means is a saline solution.

10. The temperature dependent shutter release of claim 6 in which saidliquid-filled means is formed as an elastic toroidal shaped memberhaving a quantity of liquid contained therein, said elastic toroidalshaped member being positioned between said housing and said actuatormeans.

11. A temperature dependent shutter release for a photographic camera,said temperature dependent shutter release comprising:

a housing;

actuator means movable between a first position in which said shutterrelease is in a pre-exposure con-,

ditionand a secondposition in which said shutter release initiates aphotographic exposure;

contact means positioned in the path of movement of said actuator means,at least one of said contact means being movable in response to saidactuator means movement for opening an electrical circuit when saidactuator means is in its said first position and being further movableto close said electrical circuit when said actuator means is in its saidsecond position; and liquid-filled means operative to prevent saidactuator means from moving from said first position to said secondposition when the temperature of said liquid-filled means is below apredetermined value. 12. A photographic camera for mounting a film unitat a focal plane, for subsequently exposing the film unit and thenprocessing the film unit, the film unit being of a self-developing typehaving a photosensitive sheet and a pod of processing fluid suitable tobe distributed across the photosensitive'sheet after its exposure tofacilitate the development of a viewable image, the processing fluidwithin the pod being substantially inoperative for such processing attemperatures below a given temperature, said camera including:

' actuator means movable between a first position and a second position;means responsive to the movement of said actuator means from its saidfirst position to its said second position for initiating a function ofsaid camera; and r liquid-filled means operative to prevent saidactuator means from moving from its said first position to its saidsecond position when the temperature of said liquid-filled means isbelow said given temperature, said liquid-filled means being located inthe path of movement of at least a portion of said actuator means whensaid actuator means is moved from its said first position towards itssaid second position.

" UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PatentNo.3,824,611 Dated July 15, 1974 Inventor(s) Edwin H. Land and David V.Cronin 4 It is certified that error appears in the above-identifiedpatent and that said Letters'Patent are hereby corrected as shown below:

In the Title, change "IMII'ATING" to -INITIATING-.

Signed and sealed this 29th day of October 1974.

(SEAL) Attest:

C. MARSHALL DANN McCOY M. GIBS ON JR. ,Atteating Officer I Commissionerof Patents I I uscoMM-oc 60376-P69 ".S. GOVIIIIIIIIIT IIHIIIIG OIIICII!!! O-lCl-lll UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIONPatent No. 3,824,611 Dated July 16, 1974 Inventox-(s) Edwin H Land andDavid V. Cronin It is certified that e'rror appears in theabove-identified patent and that; said Letters-Patent are herebycorrected as shown below:

In the Title, change "'IMITATING" to -INITIATING.

Signed and sealed this 29th day of October 1974.

(SEAL) Att'est:

McCOY M. szas on JR. c. MARSHALL DANN ,Atteating Officer Commissioner ofPatents USCOMM-OC BOMB-P69 l 0.x. GOVIIIIIIIII alumna orrlct u" o-iu-nlFORM Po-mso (10-69) 1 v

1. A temperature dependent shutter release for a photographic camera,said temperature dependent shutter release comprising: a housing;actuator means extending through said housing, said actuator means beingmovable between a first position in which said shutter release is openand a second position in which said shutter release is closed; andliquid-filled means operative to prevent said actuator means from movingfrom said first position to said second position when the temperature ofsaid liquid-filled means is below a predetermined position, saidliquid-filled means being formed as an elastic toroidal shaped memberhaving a quantity of liquid contained therein, said elastic toroidalshaped member being positioned between said housing and said actuatormeans.
 2. The temperature dependent shutter release of claim 1 in whichsaid liquid contained within said elastic toroidal shaped member isselected having a predetermined freezing point, said elastic toroidalshaped member being operative to prevent said movement of said actuatormeans from said first position to said second position when saidphotographic camera is subjected to temperatures below saidpredetermined freezing point of said liquid.
 3. The temperaturedependent shutter release of claim 2 in which said elastic toroidalshaped member is operative to comply with said movement of said actuatormeans from said first position to said second position when saidphotographic camera is subjected to temperatures above saidpredetermined freezing point of said liquid.
 4. The temperaturedependent shutter release of claim 3 in which said liquid containedwithin said elastic toroidal shaped member is an aqueous solution. 5.The temperature dependent shutter release of claim 4 in which saidliquid contained within said elastic toroidal shaped member is a salinesolution.
 6. A temperature dependent shutter release for a photographiccamera, said temperature dependent shutter release comprising: ahousing; actuator means movable between a first position in which saidshutter release is in a pre-exposure status and a second position inwhich said shutter release initiates a photographic exposure; andliquid-filled means including a liquid contained therein having apredetermined freezing point, said liquid-filled means being operativeto prevent the movement of said actuator means from said first positionto said second position when said photographic camera is subjected totemperatures below said predetermined freezing point of said liquid. 7.The temperature dependent shutter release of claim 6 in which saidliquid-filled means is operative to elastically comply with saidmovement of said actuator means from said first position to said secondposition when said camera is subjected to temperatures above saidpredetermined freezing point of said liquid.
 8. The temperaturedependent shutter release of claim 7 in which said liquid containedwithin said liquid-filled means is an aqueous solution.
 9. Thetemperature dependent shutter release of claim 8 in which said ilquidcontained within said liquid-filled means is a saline solution.
 10. Thetemperature dependent shutter release of claim 6 in which saidliquid-filled means is formed as an elastic toroidal shaped memberhaving a quantity of liquid contained therein, said elastic toroidalshaped member being positioned between said housing and said actuatormeans.
 11. A temperature depEndent shutter release for a photographiccamera, said temperature dependent shutter release comprising: ahousing; actuator means movable between a first position in which saidshutter release is in a pre-exposure condition and a second position inwhich said shutter release initiates a photographic exposure; contactmeans positioned in the path of movement of said actuator means, atleast one of said contact means being movable in response to saidactuator means movement for opening an electrical circuit when saidactuator means is in its said first position and being further movableto close said electrical circuit when said actuator means is in its saidsecond position; and liquid-filled means operative to prevent saidactuator means from moving from said first position to said secondposition when the temperature of said liquid-filled means is below apredetermined value.
 12. A photographic camera for mounting a film unitat a focal plane, for subsequently exposing the film unit and thenprocessing the film unit, the film unit being of a self-developing typehaving a photosensitive sheet and a pod of processing fluid suitable tobe distributed across the photosensitive sheet after its exposure tofacilitate the development of a viewable image, the processing fluidwithin the pod being substantially inoperative for such processing attemperatures below a given temperature, said camera including: actuatormeans movable between a first position and a second position; meansresponsive to the movement of said actuator means from its said firstposition to its said second position for initiating a function of saidcamera; and liquid-filled means operative to prevent said actuator meansfrom moving from its said first position to its said second positionwhen the temperature of said liquid-filled means is below said giventemperature, said liquid-filled means being located in the path ofmovement of at least a portion of said actuator means when said actuatormeans is moved from its said first position towards its said secondposition.